1. Field of the Invention
This invention relates to an expansion joint for use between spaced-apart ends of adjacent sections of a highway, bridge or the like to sealingly accommodate changes in the spacing between the sections as a result of thermal contraction and expansion. More particularly, this invention relates to an expansion joint of the foregoing character whose components are readily accessible for purposes of inspection and repair or replacement thereof without the need to destructively remove sections of the concrete pavement or other structure in which such expansion joint is incorporated.
2. Description of the Prior Art
Various types of expansion joints for highways, bridges and the like are known in the prior art for accommodating relatively large changes in spacing between the opposed ends of adjacent sections thereof as a result of thermal expansion and contraction. One of the popular types of these expansion joints is the so-called Maurer joint, which is named after the West German firm that developed such joint. A Maurer joint incorporates opposed sets of boxes which are fabricated from a metallic material, usually a rolled carbon steel, and which are embedded at spaced apart locations in the opposed ends of adjacent sections of a highway, for example. One or more intermediate rails extending transversely of the sections are placed between the adjacent sections and are supported on support rails which extend between the metal boxes and transversely of the intermediate rails which are supported thereby. The support rails, in turn, are supported at their ends in the fabricated boxes. Springs are usually placed on opposite sides of each of the support rails to center each intermediate rail, each of which is attached to one of the support rails, between adjacent intermediate rails. Elastomeric membranes are placed between an edge rail at the edge of each section of the highway and the intermediate rail which is adjacent to it, and between each adjacent pair of intermediate rails in an expansion joint having two or more of such intermediate rails, to seal the expansion joint against the ingress of water, dirt and debris, to thereby prevent corrosion or other damage to the elements of the expansion joint or damage to the ends of the highway which incorporates the expansion joint.
Heretofore, in a Maurer joint of the foregoing character the tops of the fabricated metal boxes thereof were positioned below the driving surface of the highway which incorporates such metal boxes, with an appreciable depth of concrete or other pavement material placed thereover to protect the metal boxes and their components from the ingress of water, dirt and debris. Unfortunately, in such a construction it is not possible to inspect the metal boxes and their components after the covering thereof with the pavement material, or to repair or replace the metal boxes or any of their components, without destructively removing the covering layer of pavement material. Thus, the inspection and maintenance of known types of Maurer expansion joints, as described, is a rather time-consuming and expensive procedure.